264 THE BACILLUS OF MALIGNANT EDEMA 



microscopically long, slender rods are seen; often also pseudofilaments. 

 The bacilli somewhat resemble anthrax bacilli, but have rounded 

 and sometimes even pointed ends, instead of square ends. 



Morphology and Staining Properties. The bacillus of malignant 

 edema varies much in length; its average is from 2 to 4 micra; some 

 individual bacteria are much longer, and the pseudofilaments may 

 have a length of 15 micra. The diameter of 

 FIG. 136 the rods and pseudofilaments is generally 



^ 1 micron. Spores are found in moderate 



. numbers in the serous exudates; they are 



*y very numerous in cultures. They are, how- 



/ A ever, only found in the single bacilli, not in 

 / the filaments; they are oval, generally situ- 



ated in the middle, occasionally toward the 

 Bacillus of malignant edema, end of the rods; they bulge out the bacillus 

 (Park.) somewhat, but not to such an extent as the 



symptomatic anthrax bacilli. Jensen found 



that some stems of malignant edema bacilli form pseudofilaments 

 either in the cultures or in bodies of animals. The bacillus is motile 

 and possesses numerous flagella. The organism stains with the 

 ordinary watery anilin stains and keeps Gram's stain if the decolor- 

 ization in alcohol is not continued very long. 



Cultural Properties. The organism is strictly anaerobic. It grows 

 at room temperature and in the incubator in the absence of oxygen, 

 on all the ordinary media, particularly well in the presence of a salt 

 of formic acid or glucose. In gelatin stick cultures, small, white, 

 shining round colonies are formed along the stab. As these increase 

 in size gas-bubbles appear and the medium becomes liquefied and is 

 changed into a grayish-white cloudy fluid. Agar becomes cleft and 

 torn in consequence of the gas formation during the growth. Bouillon 

 becomes cloudy and forms a whitish sediment after two to three 

 days; the upper strata then clear up and small gas-bubbles continue 

 to rise to the surface. The bacillus grows well on coagulated blood 

 serum. On potatoes it multiplies likewise, but the growth which it 

 forms is invisible. When growing in blood serum the bacillus produces 

 a very fetid smell, due to the putrid decomposition of the serum 

 albumin. 



Resistance. The spores of the bacillus of malignant edema are 

 very resistant, and in this respect act much like the spores of the 

 Bacillus sarcophysematos bovis. Sunlight appears to have little 

 effect upon them, likewise 5 per cent, carbolic acid. 



Natural Infection. This generally takes place from cutaneous 

 wounds, from the denuded surface of the parturient uterus, etc. In- 

 fections in man and the horse have been seen following medicinal 

 injections with unclean hypodermic syringes. The mucous mem- 

 branes of the mouth and pharynx also form a portal of entrance. It 

 is believed that the organism or its spores may enter the circulation 



